1. Field of the Invention
The present invention relates to disk cartridges for storing digital information, and more particularly, to a disk cartridge having head loading/unloading ramps within the cartridge to facilitate the loading and unloading of read/write heads onto a storage medium within the cartridge.
2. Description of the Prior Art
Removable disk cartridges for storing digital electronic information typically comprise an outer casing or shell that houses a disk-shaped magnetic, magneto-optical or optical storage medium upon which information can be stored. The cartridge shell often comprises upper and lower halves that are joined together to house the disk. The disk is mounted on a hub that rotates freely within the cartridge. When the cartridge is inserted into a disk drive, a spindle motor in the drive engages the disk hub in order to rotate the disk within the cartridge at a given speed. The outer shell of the cartridge typically has an opening near one edge to provide the recording heads of the drive with access to the disk. A shutter or door mechanism is often provided to cover the head access opening when the cartridge is not in use to prevent dust or other contaminants from entering the cartridge and settling on the recording surface of the disk.
Disk drives for use with such removable disk cartridges typically employ either a linear actuator mechanism or a radial arm actuator mechanism for positioning the read/write head(s) of the disk drive on the recording surface(s) of the storage medium, or disk. Because the disk cartridges are designed to be removable from the drive, the linear or radial arm actuators must be able to move off, and away from, the storage medium to a retracted position in order to prevent damage to the head(s) when a cartridge is inserted and removed from the disk drive.
Many removable cartridge disk drives employ a pair of opposing read/write heads for recording and reproducing information on both sides of a storage medium. Typically, the opposing heads are disposed on flexible suspension arms at the distal end of an actuator that allow the heads to fly closely over the respective surfaces of the rotating disk. The opposing heads must be spread apart as they approach the edge of the disk during a head loading operation in order to avoid collision with the edge of the disk. Similarly, when the heads are unloaded from the disk, they must again be spread apart to avoid collision with the edge of the disk and each other.
A mechanism for controlling the loading and unloading of heads in connection with a linear actuator mechanism is disclosed in commonly assigned, co-pending patent application Ser. No. 08/324,895, filed Oct. 18, 1994, entitled "Head Load/Unload and Cleaning in a Data Storage Device". As disclosed therein, wings are attached to the heads that act as lifters to control the vertical position of the heads. The wings are in close proximity to the heads to fully ensure that the motion of the wing is the motion of the heads. The wings ride on opposed ramps fixedly disposed in the drive as the carriage of the linear actuator moves toward and away from the disk.
U.S. Pat. No. 4,965,685 (Thompson et al.) discloses a head loading mechanism for use with a radial arm voice coil actuator. The radial arm actuator comprises a bifurcated actuator arm that has upper and lower suspension arms mounted at its distal end. Magnetic heads are mounted on the ends of the respective suspension arms. The head loading mechanism of Thompson et al. comprises an elongate head load arm that is pivotally mounted within the disk drive. Ramped prongs are formed at the distal end of the head load arm. When the disk drive is not in use, the suspension arms are separated by, and rest upon, the ramped prongs. When a disk cartridge is inserted into the disk drive, the actuator arm moves toward the disk cartridge causing the suspension arms to move down the ramped prongs and onto the recording surfaces of the storage medium.
U.S. Pat. No. 4,683,506 (Toldi et al.) discloses yet another mechanism for separating a pair of opposing read/write heads during cartridge insertion and for subsequently bringing the heads together onto the surface of a storage medium. Like other prior art mechanisms, this mechanism is also mounted in the disk drive.
Because the head loading/unloading mechanisms of the prior art are mounted in their respective disk drives, they must be designed to account for the relatively loose tolerances on the positioning of a disk cartridge within the disk drive. The vertical displacement of the read/write heads during head loading operations must be sufficiently large to accommodate worst case vertical positioning of a disk cartridge within the drive. Unfortunately, such large vertical displacement of the read/write heads adversely affects other tolerances in the disk cartridge and disk drive, and the increased vertical travel of the read/write heads affects the speed of the head loading operation. Accordingly, there is a need for a more efficient head loading/unloading mechanism that provides more accurate and controlled positioning of the read/write heads relative to the storage medium within a disk cartridge. The present invention satisfies this need.